Certain embodiments of present invention relate to an electrical connector for interconnecting electronic components, such as a battery and printed circuit board. More particularly, certain embodiments of the present invention relate to an electrical connector having spring-biased plunger contacts for an electrical connector.
In certain applications, such as a cell phone with a charger, a battery in the cell phone is electrically connected to a printed circuit board in the charger to be recharged when the cell phone is placed in the charger. Typically, the charger includes an electrical connector with spring-biased plunger contacts connected to the printed circuit board. The plunger contacts extend into the cradle area in the charger where the cell phone is placed. The plunger contacts are positioned in the cradle area to align with mating contacts on the cell phone when the cell phone is inserted into the cradle area.
The typical electrical connector of the foregoing type includes a rectangular housing with a mating face opposite an open side of the housing. The housing carries cylindrical casings that are open at one end along the mating face and that have closed contact bases at an opposite end along the open side of the housing. The closed contact bases are connected to the printed circuit board. The casings retain springs and cylindrical or bullet shaped contacts with the springs positioned between an end of the bullet contacts and contact bases. An opposite end of the bullet contacts extends partially through the open ends of the casings at the mating face of the housing. When a cell phone is mounted to the mating face, the bullet contacts engage mating contacts on the cell phone to join its battery. The bullet contacts are pushed downward into the casings, thereby compressing the springs. Thus an electrical path is formed that extends from the battery to the printed circuit board successively through the mating contacts on the cell phone to the bullet contacts, the springs, and the contact bases in the charger.
However, the typical electrical connector of the above noted type suffers from certain drawbacks. First, the cylindrical bodies of the bullet contacts are manufactured by a screw-machining process which is expensive and time-consuming because each bullet contact is machined from pre-existing metal stock. Secondly, the electrical connectors are time-consuming and expensive to assemble because each spring and bullet contact is separately loaded into a casing, and then the casings are loaded into the housing. Finally, the electrical path through the electrical connector is extensive. An electrical current travels from the bullet contact through the coils of the spring before reaching the contact base. The electrical current may pass through the length of the spring directly along the coils or, if the spring is completely compressed and the coils are contacting each other, from coil to coil. Because either such electrical path through the spring is extensive, an electrical current traveling through the spring encounters resistance. To overcome the resistance of the electrical path, more power is required to maintain an adequate supply of electrical current between the battery and the printed circuit board.
Therefore, a need exists for an electrical connector that overcomes the above problems and addresses other concerns experienced in the prior art.
Certain embodiments provide for an electrical connector including a housing having a contact retention chamber and first and second mating faces configured to engage mating contacts. The electrical connector includes a cap having a first end configured to engage a mating contact and a second end being open. The electrical connector includes a plunger contact having a first end projecting from the housing. The first end is configured to engage a mating contact. The plunger contact has a second end that includes a spring retention area and that telescopically communicates with the cap. The plunger contact and the cap move relative to one another along a contact motion axis. The electrical connector includes a spring provided between the plunger contact and the cap that engages the spring retention area of the plunger contact along a contact/spring interface. At least one of the plunger contact and cap define the contact/spring interface to have an angled interface that biases the spring at an acute angle to the contact motion axis in order to induce a lateral binding force between the plunger contact and the cap. The lateral binding force causes the plunger contact and the cap to maintain a direct electrical connection therebetween independent of the spring during movement along the contact motion axis.